Method and system for workload balancing to assist in power grid load management

ABSTRACT

A method and system for workload balancing to assist in power grid load management. The method includes receiving a request to perform a task at a site powered by connection to an AC power grid, the task comprising either data processing or manufacturing an article; measuring an AC frequency of the AC power grid to obtain a current AC frequency; and performing or not performing the task at the site based on the current AC frequency.

RELATED APPLICATIONS

This Application is a continuation of U.S. patent application Ser. No.12/619,746 filed on Nov. 17, 2009.

FIELD OF THE INVENTION

The present invention relates to the field of power grid management;more specifically, it relates to a method and system for workloadbalancing to assist in power grid management.

BACKGROUND

Currently, electric power providers must constantly balance powergeneration capacity to match real-time demand. This power supply/demandbalancing requires bringing on and off line auxiliary generatingfacilities. This process not only increases the costs of generatingpower, but provides little incentive for power conservation.Accordingly, there exists a need in the art to mitigate the deficienciesand limitations described hereinabove

SUMMARY

A first aspect of the present invention is a method, comprising:receiving a request to perform a task at a site powered by connection toan AC power grid, the task comprising either data processing ormanufacturing an article; measuring an AC frequency of the AC power gridto obtain a current AC frequency; and performing or not performing thetask at the site based on the current AC frequency.

A second aspect of the present invention is a method, comprising:receiving a request to perform a task at a site powered by connection toan AC power grid, the task either comprising data processing ormanufacturing an article; periodically measuring an AC frequency of theAC power grid to obtain a current AC frequency; starting the task at thesite on a computer system or a manufacturing tool connected to the ACpower grid when the current AC frequency is equal to or greater than athreshold AC frequency; and after the receiving a request to perform atask, the periodically measuring an AC frequency of the AC power gridand the starting the task at the site, then periodically measuring an ACfrequency of the AC power grid to obtain a periodic AC frequency and ifthe periodic AC frequency is lower than the threshold AC frequency thenstopping the task and restarting the task from where the task wasstopped when the periodic AC frequency is again greater than thethreshold AC frequency.

A third aspect of the present invention is a computer system comprisinga processor, an address/data bus coupled to the processor, and acomputer-readable memory unit coupled to communicate with the processor,the memory unit containing instructions that when executed by theprocessor implement a method for workload balancing to assist in powergrid load management, the method comprising the computer implementedsteps of: receiving a request to perform a task at a site powered byconnection to an AC power grid, the task comprising either dataprocessing or manufacturing an article; determining a current ACfrequency of the AC power grid from frequency measurements of the ACpower grid; and issuing instructions to perform or not perform the taskat the site based on the current AC frequency.

A fourth aspect of the present invention is a computer system comprisinga processor, an address/data bus coupled to the processor, and acomputer-readable memory unit coupled to communicate with the processor,the memory unit containing instructions that when executed by theprocessor implement a method for workload balancing to assist in powergrid load management, the method comprising the computer implementedsteps of: receiving a request to perform a task at a site powered byconnection to an AC power grid, the task either comprising dataprocessing or manufacturing an article; periodically determining acurrent AC frequency of the AC power grid based on frequencymeasurements of the AC power grid; issuing instructions to start thetask at the site on a computer system or a manufacturing tool connectedto the AC power grid when the current AC frequency is equal to orgreater than a threshold AC frequency; and after the receiving a requestto perform a task, the periodically measuring an AC frequency of the ACpower grid and the starting the task at the site, then periodicallymeasuring an AC frequency of the AC power grid to obtain a periodic ACfrequency and if the periodic AC frequency is lower than the thresholdAC frequency then stopping the task and restarting the task from wherethe task was stopped when the periodic AC frequency is again greaterthan the threshold AC frequency.

These and other aspects of the invention are described below.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the invention are set forth in the appended claims. Theinvention itself, however, will be best understood by reference to thefollowing detailed description of an illustrative embodiment when readin conjunction with the accompanying drawings, wherein:

FIG. 1 a diagram illustrating an exemplary pair of linked dataprocessing facilities linked to different power grids according to anembodiment of the present invention;

FIG. 2 is a diagram of an exemplary power-monitoring device according tothe present invention;

FIG. 3 is a diagram illustrating an exemplary pair of linkedmanufacturing facilities linked to different power grids according to anembodiment of the present invention;

FIG. 4 is a flow diagram illustrating a first method of workloadbalancing for power grid management according to embodiments of thepresent invention;

FIG. 5 is a flow diagram illustrating a second method of workloadbalancing for power grid management according to embodiments of thepresent invention;

FIG. 6 is a flow diagram illustrating a third method of workloadbalancing for power grid management according to embodiments of thepresent invention; and

FIG. 7 is a schematic block diagram of a general-purpose computer.

DETAILED DESCRIPTION

The direction of alternating current periodically changes and results ina sinusoidal change of voltage from a maximum positive value to aminimum negative value over time. Thus, the frequency of AC power can bedefined on a plot of voltage versus angular frequency the number ofangular frequency cycles (0 to 360 degrees) per unit of time and theusual unit of measurement is Hertz, also commonly cycles/second, oftenshorted to cycles. AC power grids are designed to run most efficientlyat a nominal frequency. In one example, the nominal operating frequencyof an AC power grid is 60 Hz. In one example, the nominal operatingfrequency of an AC power grid is 50 Hz. The AC power grids of interestin the present invention are those bulk electrical transfer networks andsub-networks for transferring electricity from commercial powergenerating stations to consumers, such a households and businesses andfactories. In one example, an AC power grid comprises a main powerplant, an optional auxiliary power plant, and transmission lines.

As power demand (e.g., power consumption or load) increases on an ACpower grid, the frequency decreases. In order to increase the frequency,either an increase in power generation or decrease in demand isrequired. Power generation can be increased by running main plants athigher output or bringing auxiliary power plants on line. Increasing theoutput of main power plants increases the maintenance costs anddecreases the life of the plant, resulting in increased costs. Bringingauxiliary power plants online increase costs because auxiliary powerplants often use fuels that are more expensive and/or are less efficientand thus more costly per unit of energy generated. As power demanddecreases on an AC power grid, the frequency increases. In order todecrease the frequency, either a decrease in power generation orincrease in demand is required. The methods and systems of the presentinvention utilize changes in frequency in the power grid to as aworkload management tool to assist in keeping the frequency of the powergrid at or close to nominal.

FIG. 1 a diagram illustrating an exemplary pair of linked dataprocessing facilities linked to different power grids according to anembodiment of the present invention. In FIG. 1, a first data processingsite 100A (site A) is connected to a first power grid 105A (power gridA) via an incoming power line 110A. First data processing site 100Aincludes a power monitor 115A, a job dispatch unit 120A and a dataprocessor 125A, which includes a job queue 127A. Power monitor 115A anddata processor 125A are connected to incoming power line 110A. Jobdispatch unit 120A is also connected to incoming power line 110A, butgenerally consumes a far less amount of power compared to data processor125A. Power monitor 125A monitors the AC frequency of on incoming powerline and transmits a control signal 130A to job dispatch unit 120A. Jobdispatch unit 120A communicates with data processor 125A via datatransmission lines 135A.

Also in FIG. 1, a second data processing site 100B (site B) is connectedto a second power grid 105B (power grid B) via an incoming power line110B. First and second power grids 105A and 105B are sufficientlyelectrically isolated from each other so a change in AC frequency on onedoes not affect the AC frequency on the other. Second data processingsite 100B includes a power monitor 115B, a job dispatch unit 120B and adata processor 125B, which includes a job queue 127B. Power monitor 115Band data processor 125B are connected to incoming power line 110B. Jobdispatch unit 120B is also connected to incoming power line 110B, butgenerally consumes a far less amount of power compared to data processor125B. Power monitor 125B monitors the AC frequency of an incoming powerline and transmits a control signal 130B to job dispatch unit 120B. Jobdispatch unit 120B communicates with data processor 125B via datatransmission lines 135B.

While two sites 100A and 100B are illustrated in FIG. 1, there may bemore than two sites linked together communications wise. The onlyrequirement is that the different sites can perform at least some of thesame job processing and be equipped with similar power monitors andsimilar and compatible job dispatch units. However the sites do not allneed to be linked in the same way. For example, a first and second sitecould be linked via the Internet and a third site linked to the firstand second sites by a private network. Additionally, sites may havemultiple linkages to each other with one linkage for exchanginglogistics data and another, more secure linkage for transferring theactual jobs to be processed.

The types of work data processors 125A and 125B can perform involve dataprocessing on computer systems. Examples of data processing includeprocessing banking and securities transactions, generating and/ormailing billing statements, generating and/or mailing accountstatements, processing requests for information on servers (e.g., searchengines), catalog look-up or technical reference lookup. When jobs arenot being run, the data processor, which may include data storage units,displays, incidental mechanical systems such as printers and envelopestuffers, and other devices does not consume as much power as whenprocessing. Alternatively, the data processor can be turned off.

In one example, job dispatch units 120A and 120B may be softwareapplications running on general-purpose computers. In one example, dataprocessors 125A and 125B may be software applications running ongeneral-purpose computers.

The nature of the communications between job dispatch unit 120A and jobdispatch unit 120B is described in detail infra with respect to FIGS. 4,5 and 6, but generally involves information for deciding to process jobsat site A or site B based on capability to perform the processing,capacity and AC frequency at the respective sites. The communicationsalso include the issuing of related instructions.

Job dispatch unit 120A is connected to the Internet 140 by link 145A.Job dispatch unit 120B is connected to the Internet 140 by link 145B.The links 145A and 145B may be public or virtual private networkconnections. Alternatively, the two job dispatch units 120A and 120B maybe connected directly via a wired or wireless telephone connection or bya wired or wireless private network. This connection allows the twosites to exchange frequency information, workload information and ifnecessary, to transfer the actual work and issue instructions.

FIG. 2 is a diagram of an exemplary power-monitoring device according tothe present invention. In FIG. 2, power monitor 115 includes a frequencydetector 150, an optional data storage unit 155, a microprocessor 160and an optional memory unit 165. Power monitor 115 represents powermonitors 115A and 115B of FIG. 1 and power monitors 115C and 115D ofFIG. 3. Frequency detector 150 is connected to an incoming power line110 and monitors the frequency of incoming power line 110. Thisinformation is passed to data storage unit 155 and then tomicroprocessor 160 (or directly to microprocessor 160) which generated acontrol signal 130 which includes information that a job dispatch unitsuch as job dispatch units 120A and 120B of FIG. 1 can use. In oneexample, power monitor 115 will sample the AC frequency over a selectedtime range and transmit that information. In one example, power monitor115 will sample the AC frequency over a selected time range, analyze thedata and then generate a signal indicating the frequency is too lowprocess jobs or is high enough to process jobs.

Alternatively, it is possible to incorporate the functions of datastorage unit 155, microprocessor 160 and memory unit 165 into a jobdispatch unit such as job dispatch units 120A and 120B of FIG. 1.Alternatively, data storage unit 155, microprocessor 160 and memory unit165 may be components of a general-purpose computer.

FIG. 3 is a diagram illustrating an exemplary pair of linkedmanufacturing facilities linked to different power grids according to anembodiment of the present invention. In FIG. 3, a first manufacturingsite 100C (site C) is connected to a first power grid 105C (power gridC) via an incoming power line 110C. First manufacturing site 100Cincludes a power monitor 115C, a job dispatch unit 120C andmanufacturing tool 125C which includes a job queue 127C. Firstmanufacturing site 100C also includes a material inventory 170C. Powermonitor 115C and manufacturing tool 125C are connected to incoming powerline 110C. Job dispatch unit 120C is also connected to incoming powerline 110C, but generally consumes a far less amount of power compared tomanufacturing tool 125C. Power monitor 125C monitors the AC frequency ofon incoming power line and transmits a control signal 130C to jobdispatch unit 120C. Job dispatch unit 120C communicates withmanufacturing tool 125C via data transmission lines 135C and materialinventory via data transmission lines 175C.

Also in FIG. 3, a second manufacturing site 100D (site D) is connectedto a second power grid 105D (power grid D) via an incoming power line110D. Second manufacturing site 100D includes a power monitor 115D, ajob dispatch unit 120D, a manufacturing tool 125C, which includes a jobqueue 127D. Second manufacturing site 100C also includes a materialinventory 170D. Power monitor 115D and manufacturing tool 125D areconnected to incoming power line 110D. Job dispatch unit 120D is alsoconnected to incoming power line 110D, but generally consumes a far lessamount of power compared to manufacturing tool 125D. Power monitor 125Dmonitors the AC frequency of on incoming power line and transmits acontrol signal 130D to job dispatch unit 120D. Job dispatch unit 120Dcommunicates with manufacturing tool 125D via data transmission lines135D and material inventory 170D via data transmission lines 175D.

While two sites 100C and 100D are illustrated in FIG. 1, there may bemore than two sites linked together communications wise. The onlyrequirement is that the different sites can manufacture at least some ofthe same article(s) and be equipped with similar power monitors andsimilar and compatible job dispatch units. However the sites do not allneed to be linked in the same way. For example, a first and second sitecould be linked via the Internet and a third site linked to the firstand second sites by a private network. Additionally, sites may havemultiple linkages to each other with one linkage for exchanginglogistics data and another, more secure linkage for transferring theactual jobs to be processed.

The articles that manufacturing tools 125C and 125D can fabricate islimited only by the cost of duplicating capabilities. Thus, thisembodiment of the present invention can be applied to almost anymanufactured article.

In one example, job dispatch units 120C and 120D may be softwareapplications running on general-purpose computers.

The nature of the communications between job dispatch unit 120C and jobdispatch unit 120D is described in detail infra with respect to FIGS. 4,5 and 6, but generally involves information for deciding to manufacturean article at site C or site D based on capability to manufacture thearticle, capacity, material inventory and AC frequency at the respectivesites. The communications also include the issuing of relatedinstructions.

Job dispatch unit 120C is connected to the Internet 140 by link 145C.Job dispatch unit 120D is connected to the Internet 140 by link 145D.The links 145C and 145D may be public or virtual private networkconnections. Alternatively, the two job dispatch units 120C and 120D maybe connected directly via a wired or wireless telephone connection or bya wired or wireless private network. This connection allows the twosites to exchange frequency information, workload information, inventoryinformation and if necessary, to transfer the order.

A task is defined as either a request to perform a data processing jobor a request (e.g., order for) to manufacture and article. In FIGS. 3, 4and 5, a job is either a processing job as performed by the sites ofFIG. 1 or an article of manufacture as in the sites of FIG. 3. In FIGS.3 and 4, performing or not performing a task at a site is based on thecurrent AC frequency. In FIG. 6, selecting a site for a task to beperformed at is based on the current AC frequency of each site.

FIG. 4 is a flow diagram illustrating a first method of workloadbalancing for power grid management according to embodiments of thepresent invention. In optional step 200, jobs that can be run at morethan one site and the alternate site(s) are identified and registeredwith job dispatch units at one or multiple sites. In one example,registering comprises placing an identifier (e.g., job number) on alist. In step 205, as jobs are received by a receiving site the jobs areplaced in a job queue 210 but not started. In step 215, a job isselected from the job queue. In one example, job selection is based on ascheduled completion date/time. If there is no job in job queue 210 themethod waits until there is a job in the job queue. In step 220, it isdetermined if a current (i.e., most recently measured) AC frequency ishigher than a threshold AC frequency. If the current AC frequency ishigher (or alliteratively equal to) the threshold AC frequency themethod proceeds to step 225 otherwise to step 230. For example, if thenominal frequency is 60 Hz, the threshold AC frequency is 59.95 Hz andthe current AC frequency is 59.97 Hz, which is equal to or greater thanthe threshold AC frequency, then the method can proceed to step 225. Inanother example, if the nominal frequency is 60 Hz, the threshold ACfrequency is 59.95 Hz and the current AC frequency is 59.93 Hz, which isless than the threshold AC frequency, then the job cannot be started andthe method proceeds to step 230. The threshold AC frequency can begreater, less than or the same as the nominal frequency. Alternatively,when the current AC frequency is the same as the threshold AC frequencythe method could proceed to step 230 rather than step 225. In step 225,the selected job is processed and the method loops back to step 215. Theterm “job is processed” is defined as processing a job on a computersystem or manufacturing an article on a manufacturing tool(s).

Returning to step 230, in step 230 it is determined if the selected jobis a registered job (a job that can be performed at an alternate site)or otherwise identified as a job that can be performed at an alternatesite. If so the method proceeds to step 235. In step 235, the alternatesite is contacted and queried. In step 240, the alternate site isqueried as to sufficient capacity to process the selected job to meet ascheduled completion date/time. If the response in step 240 isaffirmative, the process proceeds to step 245. In step 245, thealternate site is queried as whether the AC frequency at the alternatesite is acceptable to process the selected job. If the response in step245 is affirmative, then in step 250, the selected job is transferred tothe alternate site and is ultimately processed at the alternate site.Transferring a job includes transferring all necessary data,specifications and processing instructions from the receiving site tothe alternate site. If in step 230, the selected job is not a registeredjob (or one that cannot be processed at the alternate site) or if insteps 240 or 245, the response from the alternate site was negative,then the method proceeds to step 255. In step 255, it is determined ifthe selected job needs to be released for processing to meet thescheduled completion date/time. The term “released for processing”includes (i) starting the job immediately, (ii) starting the job as soonas a data processor or manufacturing tool is available and (iii) placingthe job in any in-line queue at the data processor or manufacturing tool(as opposed to the job queue 210). In case (iii), the job queue may beorganized by first-in-first-out (FIFO) or job priority. If the selectedjob can be processed later and then the method proceeds to step 260where the selected job is returned to queue. If the selected job needsto be processed now to meet the scheduled completion date/time then themethod proceeds to step 225 where the selected job is processed by thereceiving site.

If there is more than one alternate site, then steps 235, 240 and 245are repeated until a site is found than can accept the job or until allsites have been queried. Steps 200, 205, 215, 220, 230, 235, 240, 245,250, 255 and 260 are performed by or have instructions to do the actionissued by the job dispatch unit. Step 215 may include procedures to notto select a particular job returned to queue until a predeterminedinterval of time has elapsed since the particular job was last selected.

FIG. 5 is a flow diagram illustrating a second method of workloadbalancing for power grid management according to embodiments of thepresent invention. In step 300, a site X of N sites where N is aninteger equal to or greater than 2 receives a job request. All N of theN sites are capable of processing the job request and are on differentAC power grids. In step 305, all N sites exchange data describing thecurrent AC frequency of the AC power at the sites. Next in step 310,site X determines which site has the highest AC frequency or has thegreatest positive difference when the nominal AC frequency is subtractedfrom the current AC frequency. For example, a first site has a nominalAC frequency of 60 Hz and a current AC frequency of 60.05 for adifference of positive 0.05 Hz. A second site has a nominal AC frequencyof 60 Hz and a current AC frequency of 60.02 for a difference ofpositive 0.02 Hz. Thus, the first site is chosen because positive 0.05is more positive than positive 0.02. It is possible for the greatest ACfrequency to be lower than the nominal frequency. For example, a firstsite has a nominal AC frequency of 60 Hz and a current AC frequency of59.95 for a difference of negative 0.05 Hz. A second site has a nominalAC frequency of 60 Hz and a current AC frequency of 59.93 for adifference of negative 0.07 Hz. Thus, the first site is chosen, (becausenegative 0.5 is more positive than negative 0.7) even though the currentAC frequency at the first site is below nominal.

In step 315, the selected site is queried for capacity to perform thejob request. If in step 315, the selected site does have the capacity(capacity includes materials and ability to meet a scheduled completiondate/time), the method proceeds to step 320. In step 320, it isdetermined of the selected site is site X (the receiving site) and instep 325 the job is processed by the receiving site. However, if in step320, the selected site is not site X, then in step 330, the job istransferred to the selected site and in step 335; the selected siteprocesses the job. Transferring a job includes transferring allnecessary data, specifications and processing instructions from thereceiving site to the alternate site.

Returning to step 315, if the selected site does not have the capacity,then the method proceeds to step 340. In step 340, it is determined ifthere is another site to be queried. If there is another site the methodloops back to step 310, otherwise the method proceeds to step 345. Instep 345, it is determined if the selected job needs to be released forprocessing to meet the scheduled completion date/time. If the selectedjob can be processed later and then the method proceeds to optional step350 where a predetermined time delay is imposed before looping back tostep 305. If the selected job needs to be released to meet the scheduledcompletion date/time then the method proceeds to step 325. Steps 300through 345 are repeated for each job in the queue of site X. Steps 300through 345 may be performed by each of the N sites for tasks receivedby each site of the N sites.

Unlike the methods of FIGS. 4 and 5, only one site is required toperform the method of FIG. 6, thus the communication links betweenmultiple sites illustrated in FIGS. 1 and 3 is not required, but maystill be present to allow any two or all three of the methods ofrespective FIGS. 4, 5 and 6 to be performed in combination

FIG. 6 is a flow diagram illustrating a third method of workloadbalancing for power grid management according to embodiments of thepresent invention. In optional step 400, jobs that can wait, do not needto be released for processing to meet scheduled completion date/timesare registered. In step 405, jobs received are placed in job queue 410.In step 415, it is determined if the current AC frequency is higher thana threshold AC frequency. If the current AC frequency is higher (oralternatively equal to) the threshold AC frequency the method proceedsto step 420 otherwise loops back on itself. Step 415 is performed at apredetermined AC frequency-sampling rate. In step 420, a job is selectedfrom job queue 410. In one example, job selection is based on ascheduled completion date/time (e.g., date and time). Next, in step 425,processing is started on the selected job. Next, in step 430, the ACfrequency is checked. If the AC frequency is higher (or alternativelyequal to) the threshold AC frequency the method proceeds to step 435 andprocessing continues without stopping. Next in step 440, it isdetermined if the job is complete. If the job is not complete the methodloops back to step 430. Steps 430, 435 and 440 are performedperiodically while the job is being processed. If in step 440, the jobis complete, the method loop back to step 420 via connector “A.”

Returning to step 430, if in step 430 the current AC frequency dropsbelow the threshold AC frequency the method proceeds to step 445. Instep 445 it is determined if the job can be stopped. If the job cannotbe stopped, processing continues in step 435. If processing can bestopped the method proceeds to step 450, where the job processing isstopped and the job placed on hold. Next, in step 455 a decision is madeif the current AC frequency does not exceed the threshold AC frequencyto (1) relocate the job to an alternative site or (2) restart andcomplete the job with no further stoppages. Option (1) is not availablefor manufacturing jobs as performed by sites 100C and 100D of FIG. 3.

FIG. 6 includes an optional step 460 that is performed periodically. Instep 460, jobs in queue are checked to see if they are exposed tomissing a scheduled completion date/time. If a job is exposed, theexposed job is moved from job queue 410 to step 425 as soon as step 425is available to receive the exposed job. Steps 400, 405, 415, 420, 425,430, 435. 440, 445, 450, 455 and 460 are performed by or haveinstructions to do the action issued by the job dispatch unit.

Generally, the method described herein with respect to workloadbalancing for power grid management is practiced with a general-purposecomputer and the methods described supra in the flow diagrams of FIGS.4, 5 and 6 may be coded as a set of instructions on removable or hardmedia for use by the general-purpose computer.

FIG. 7 is a schematic block diagram of a general-purpose computer. InFIG. 7, computer system 500 has at least one microprocessor or centralprocessing unit (CPU) 505. CPU 505 is interconnected via a system bus510 to a random access memory (RAM) 515 storing code 575, a read-onlymemory (ROM) 520, an input/output (I/O) adapter 525 for a connecting aremovable data and/or program storage device 530 and a mass data and/orprogram storage device 535 storing data 580, a user interface adapter540 for connecting a keyboard 545 and a mouse 550, a port adapter 555for connecting a data port 560 and a display adapter 565 for connectinga display device 570.

ROM 520 contains the basic operating system for computer system 500. Theoperating system may alternatively reside in RAM 515 or elsewhere as isknown in the art. Examples of removable data and/or program storagedevice 530 include magnetic media such as floppy drives and tape drivesand optical media such as CD ROM drives. Examples of mass data and/orprogram storage device 535 include electronic, magnetic, optical,electromagnetic, infrared, and semiconductor devices. Examples of acomputer-readable medium include a semiconductor or solid-state memory,magnetic tape, a removable computer diskette, a random access memory(RAM), a read-only memory (ROM), a rigid magnetic disk and an opticaldisk. Current examples of optical disks include compact disk-read onlymemory (CD-ROM), compact disk-read/write (CD-R/W) and DVD. In additionto keyboard 545 and mouse 550, other user input devices such astrackballs, writing tablets, pressure pads, microphones, light pens andposition-sensing screen displays may be connected to user interface 540.Examples of display devices include cathode-ray tubes (CRT) and liquidcrystal displays (LCD).

A computer program with an appropriate application interface may becreated by one of skill in the art and stored on the system or a dataand/or program storage device to simplify the practicing of thisinvention. In operation, information for or the computer program createdto run the present invention is loaded on the appropriate removable dataand/or program storage device 530, fed through data port 560 or typed inusing keyboard 545.

Thus, the embodiments of the present inventions provide methods andsystems for workload balancing top assist in power grid management.

The description of the embodiments of the present invention is givenabove for the understanding of the present invention. It will beunderstood that the invention is not limited to the particularembodiments described herein, but is capable of various modifications,rearrangements and substitutions as will now become apparent to thoseskilled in the art without departing from the scope of the invention.Therefore, it is intended that the following claims cover all suchmodifications and changes as fall within the true spirit and scope ofthe invention.

What is claimed is:
 1. A method, comprising: selecting a task to beperformed at a site powered by an AC power grid, said task comprising(i) data processing on a computer system connected to said AC power gridor (ii) manufacturing an article of manufacture on a manufacturing toolconnected to said AC power grid, measuring an AC frequency of said ACpower grid to obtain a current AC frequency; said site performing or notperforming said task at said site based on said current AC frequency;and wherein said performing or not performing said task includes: ifsaid current AC frequency is less than a threshold AC frequency,determining if an additional site powered by connection to an additionalAC power grid has sufficient data processing or manufacturing capacityto perform said task; if said additional site has sufficient dataprocessing or manufacturing capacity, then measuring an AC frequency ofsaid additional AC power grid to obtain an additional current ACfrequency; and if said additional current AC frequency is equal to orgreater than an additional threshold AC frequency then transferring saidtask from said site to said additional site.
 2. The method of claim 1,wherein said performing or not performing said task includes: if saidtask is not transferred to said additional site performing said task atsaid site on a computer system or a manufacturing tool connected to saidAC power grid if said current AC frequency is equal to or greater than athreshold AC frequency.
 3. The method of claim 1, further including:after said transferring, performing said task at said additional site onan additional computer system or on an additional manufacturing toolconnected to said additional AC power grid.
 4. The method of claim 1,further including: if said additional site does not have sufficient dataprocessing or manufacturing capacity or if said additional current ACfrequency is less than said additional threshold AC frequency thendetermining if said task needs to be released for processing to meet ascheduled completion date/time and if said task needs to be released forprocessing to meet said scheduled completion date/time then performingsaid task at said site on a computer system or a manufacturing toolconnected to said AC power grid.
 5. The method of claim 1, wherein saidthreshold AC frequency is equal to or greater than a nominal ACfrequency of said AC power grid and said additional threshold ACfrequency is equal to or greater than a nominal AC frequency of saidadditional AC power grid.
 6. A method, comprising: selecting a task tobe performed at a site powered by an AC power grid, said task comprising(i) data processing on a computer system or (ii) manufacturing anarticle on a manufacturing tool; starting said task at said site on acomputer system or a manufacturing tool connected to said AC power gridwhen a current AC frequency is equal to or greater than a threshold ACfrequency; and after said starting said task, periodically measuring anAC frequency of said AC power grid and said starting said task at saidsite, then periodically measuring an AC frequency of said AC power gridto obtain a periodic AC frequency and if said periodic AC frequency islower than said threshold AC frequency then stopping said task andrestarting said task from where said task was stopped when said periodicAC frequency is again greater than said threshold AC frequency.
 7. Themethod of claim 6, further including: continuing to periodically measuresaid AC frequency of said AC power grid to obtain said periodic ACfrequency and if said periodic AC frequency is lower than said thresholdAC frequency then stopping said task and restarting said task from wheresaid task was stopped when said periodic AC frequency is again greaterthan said threshold AC frequency until said task is complete.
 8. Themethod of claim 6, further including: while said task is stopped,determining if said task needs to be released for processing to meet ascheduled completion date/time; and if said task needs to be releasedfor processing to meet said scheduled completion date/time, thenrestarting said task from where said task was stopped and completingsaid task with no further stoppages.
 9. The method of claim 6, furtherincluding: while said task is stopped, determining if said task needs tobe released for processing to meet a scheduled completion date/time; andif said task needs to be released for processing to meet said scheduledcompletion date/time and said task is a data processing task, thentransferring said task to an alternative site having the same capabilityto perform said task as said site, said alternative site completingperformance of said task.
 10. A computer system comprising a processor,an address/data bus coupled to said processor, and a computer-readablememory unit coupled to communicate with said processor, saidcomputer-readable memory unit containing instructions that when executedby the processor implement a method for workload balancing to assist inpower grid load management, said method comprising the computerimplemented steps of: selecting a task to be performed at a site poweredby an AC power grid, said task comprising (i) data processing on acomputer system connected to said AC power grid or (ii) manufacturing anarticle of manufacture on a manufacturing tool connected to said ACpower grid; determining a current AC frequency of said AC power grid atsaid site from frequency measurements of said AC power grid; issuinginstructions to said computer system or said manufacturing tool toperform and to not perform said task on said computer system or saidmanufacturing tool at said site based on said current AC frequency;wherein the method step of issuing instructions to perform or notperform said task at said site based on said current AC frequencyincludes: if said current AC frequency is less than a threshold ACfrequency, issuing instructions to determine if an additional sitepowered by connection to an additional AC power grid has sufficient dataprocessing or manufacturing capacity to perform said task; if saidadditional site has sufficient data processing or manufacturingcapacity, then determining an additional current AC frequency of saidadditional AC power grid from frequency measurements of said additionalAC power grid; and if said additional current AC frequency is equal toor greater than an additional threshold AC frequency then issuinginstructions to transfer said task from said site to said additionalsite and wherein said threshold AC frequency is equal to or greater thana nominal AC frequency of said AC power grid and said additionalthreshold AC frequency is equal to or greater than a nominal ACfrequency of said additional AC power grid.
 11. The computer system ofclaim 10, wherein the method step of issuing instructions to perform ornot perform said task at said site based on said current AC frequencyincludes: issuing instructions to perform said task at said site on saidcomputer system or said manufacturing tool, said computer system or saidmanufacturing tool connected to said AC power grid, if said current ACfrequency is equal to or greater than a threshold AC frequency.
 12. Thecomputer system of claim 10, the method further including: saidinstructions to transfer said task from said site to said additionalsite further including additional instructions to perform said task atsaid additional site on an additional computer system or on additionalmanufacturing tool connected to said additional AC power grid.
 13. Thecomputer system of claim 10, the method further including: if saidadditional site does not have sufficient data processing ormanufacturing capacity or if said additional current AC frequency isless than said threshold AC frequency then determining if said taskneeds to be released for processing to meet a scheduled completiondate/time and if said task needs to be released for processing to meetsaid scheduled completion date/time then issuing instructions to performsaid task at said site on a computer system or a manufacturing toolconnected to said AC power grid.
 14. A method, comprising: selecting atask to be performed at a site powered by an AC power grid, said taskcomprising (i) data processing on a computer system connected to said ACpower grid or (ii) manufacturing an article of manufacture on amanufacturing tool connected to said AC power grid, measuring an ACfrequency of said AC power grid to obtain a current AC frequency; saidsite performing or not performing said task at said site based on saidcurrent AC frequency; at an additional site powered by connection to anadditional AC power grid, measuring an AC frequency of said additionalAC power grid to obtain an additional current AC frequency; if saidcurrent AC frequency is higher than said additional current ACfrequency, then performing said task at said site on a computer systemor a manufacturing tool connected to said AC power grid; and if saidadditional current AC frequency is higher than said current ACfrequency, then transferring said task to said additional site andperforming said task at said additional site on a computer system or amanufacturing tool connected to said additional AC power grid.
 15. Themethod of claim 14, further including: if said additional current ACfrequency is higher than said current AC frequency, then transferringsaid task to said additional site only if said additional site hassufficient data processing or manufacturing capacity to perform saidtask.
 16. The method of claim 15 further including: if said additionalcurrent AC frequency is higher than said current AC frequency, and saidadditional site does not have sufficient data processing ormanufacturing capacity to perform said task, and said task needs to bereleased for processing to meet a scheduled completion date/time thenperforming said task at said site on said computer system or saidmanufacturing tool connected to said AC power grid.
 17. The method ofclaim 14, wherein said performing or not performing said task includes:if said task is not transferred to said additional site performing saidtask at said site on a computer system or a manufacturing tool connectedto said AC power grid if said current AC frequency is equal to orgreater than a threshold AC frequency.
 18. A computer system comprisinga processor, an address/data bus coupled to said processor, and acomputer-readable memory unit coupled to communicate with saidprocessor, said computer-readable memory unit containing instructionsthat when executed by the processor implement a method for workloadbalancing to assist in power grid load management, said methodcomprising the computer implemented steps of: selecting a task to beperformed at a site powered by an AC power grid, said task comprising(i) data processing on computer system or (ii) manufacturing an articleon a manufacturing tool; issuing instructions to start said task at saidsite on a computer system or a manufacturing tool connected to said ACpower grid when a current AC frequency is equal to or greater than athreshold AC frequency; and after starting said task, periodicallymeasuring an AC frequency of said AC power grid to obtain a periodic ACfrequency and if said periodic AC frequency is lower than said thresholdAC frequency then stopping said task only if said task can be stoppedand restarting said task from where said task was stopped when saidperiodic AC frequency is again greater than said threshold AC frequency.19. The computer system of claim 18, the method further including:continuing to periodically measure said AC frequency of said AC powergrid to obtain said periodic AC frequency and if said periodic ACfrequency is lower than said threshold AC frequency then stopping saidtask and restarting said task from where said task was stopped when saidperiodic AC frequency is again greater than said threshold AC frequencyuntil said task is complete.
 20. The computer system of claim 18, themethod further including: while said task is stopped, determining ifsaid task needs to be released for processing to meet a scheduledcompletion date/time and either: if said task needs to be released forprocessing to meet said scheduled completion date/time, then issuinginstructions to restart said task from where said task was stopped andcompleting said task with no further stoppages; or if said task needs tobe released for processing to meet said scheduled completion date/timeand said task is a data processing task, then issuing instructions totransfer said task to an alternative site having the same capability toperform said task as said site and issuing instructions to saidalternative site to complete performance of said task.
 21. A computersystem comprising a processor, an address/data bus coupled to saidprocessor, and a computer-readable memory unit coupled to communicatewith said processor, said computer-readable memory unit containinginstructions that when executed by the processor implement a method forworkload balancing to assist in power grid load management, said methodcomprising the computer implemented steps of: selecting a task to beperformed at a site powered by an AC power grid, said task comprising(i) data processing on a computer system connected to said AC power gridor (ii) manufacturing an article of manufacture on a manufacturing toolconnected to said AC power grid; determining a current AC frequency ofsaid AC power grid at said site from frequency measurements of said ACpower grid; at an additional site powered by connection to an additionalAC power grid, determining an additional current AC frequency of saidadditional AC power grid based on frequency measurements of saidadditional AC power grid; if said current AC frequency is higher thansaid additional current AC frequency, then issuing instructions toperform said task at said site on a computer system or a manufacturingtool connected to said AC power grid; and if said additional current ACfrequency is higher than said current AC frequency, then issuinginstructions to transfer said task to said additional site and for saidadditional site to perform said task on an additional computer system oran additional manufacturing tool connected to said additional AC powergrid.
 22. The computer system of claim 21, the method further including:if said additional current AC frequency is higher than said current ACfrequency, then issuing instructions to transfer said task to saidadditional site only if said additional site has sufficient dataprocessing or manufacturing capacity to perform said task.
 23. Thecomputer system of claim 22, the method further including: if saidadditional current AC frequency is higher than said current ACfrequency, and said additional site does not have sufficient dataprocessing or manufacturing capacity to perform said task, and said taskneeds to be released for processing to meet a scheduled completiondate/time then performing said task at said site on said computer systemor said manufacturing tool connected to said AC power grid.